Curious to try Unity, I am trying to update the correct drivers for the Intel GMA 500 with trying to step on https: / / launchpad.net / ~ GMA500 / + archive/psb110 but it hangs when booting ubuntu 11:04.
Finally I tried the next step on https: / / code.launchpad.net / ~ GMA500 / + archive / emgd as follows:
sudo apt-add-ppa repository: gma500/emgd
sudo apt-get updatesudo apt-get install xorg-emgd emgd-dkmssudo emgd-xorg-conf
and Unity immediately become the default interface.
rebooted for the changes to take effect.
UPDATE!
You have to try the steps from http://ubuntuforums.org/showthread.php?t=1229345&page=394 to correct brightness.